I’m developing an app, and I think my client is creating too many socket/channel connection, so I decided to setup some watchers. I followed Chris McCord’s code in this SO post: https://stackoverflow.com/questions/33934029/how-to-detect-if-a-user-left-a-phoenix-channel-due-to-a-network-disconnect

I created both a ChannelWatcher, and a SocketWatcher. The ChannelWatcher is working as I would expect, however the SocketWatcher is a bit weird, the pid that connects to the socket seems to die shortly after connecting (even though from the client side, the socket is still connected).

  @impl true
  def connect(%{"token" => token}, socket, _connect_info) do
    case Authentication.resource_from_access_token(token) do
      {:ok, user} ->
        SocketWatcher.monitor(self(), {__MODULE__, :on_disconnect, [user.id]})
        {:ok, Phoenix.Socket.assign(socket, current_user: user)}

      _ ->
        :error
    end
  end

  ...

  def on_disconnect(pid) do
    IO.puts("#{pid}'s socket disconnected")
  end

However the PID seems to die immediately

SocketWatcher monitoring #PID<0.3054.0>  <- Logged from the SocketWatcher.monitor function
:ok
[debug] CONNECTED TO MyAppWeb.UserSocket in 3ms
  Transport: :websocket
  Serializer: Phoenix.Socket.V2.JSONSerializer
  Parameters: %{"token" => "ACCESS_TOKEN", "vsn" => "2.0.0"}
#PID<0.3054.0>'s socket disconnected  <- Logged from UserSocket's on_disconnect function

Perhaps I misunderstand how Sockets work, but I thought it was a long-lasting PID that holds the connection. How do I find where the Sockets are listed? Are they stored in an ETS table? Can I watch them like I would a channel’s PID?